One theory being propagated is that all forms of Autism are nothing more than mercury poisoning. The Food and Drug Administration in the United States, and the Center for Disease Control have dismissed this, but it hasn't stopped the panic stricken parents screaming conspiracy theories. This particularly attacks a financial arrangement (supposed) between pharmaceutical companies and the FDA and the CDC, in order to try to retain a preservative known as thimerosal (AKA thiomersal outside the US) which was used to preserve vaccines. Invented in 1931, the alarmists claim that this ties in with Leo Kanner's paper on Autism in 1943. To add to this, there is also a claim that in or around 1990 the amount of thimerosal was increased, leading to (supposedly) an increase in the diagnosis rate of AS